The invention relates to an open-end spinning frame with a plurality of spinning assemblies and with a travelling servicing device, movable to the respective spinning assemblies to exchange full bobbins for empty tubes. The servicing device is equipped with devices for lifting off a bobbin together with a bobbin holder from a friction roll, to open the bobbin holder and eject the bobbin, as well as with an empty tube engaging device that engages an empty tube and sets it in the bobbin holder.
In a known construction (German OS No. 2,306,907), an empty tube is ready at a place on the travelling device adjacent to the bobbin holder of the open end spinning frame. By means of a swingable lever that has an engaging roll, an empty tube is laid in, in the bobbin exchange operation, between the full bobbin and a section roll that drives the bobbin. Here the empty tube acts as a reversing drive will respect to the full bobbin, whereby part of the yarn already wound by the bobbin is again wound off and wound as yarn reserve on the empty tube. Finally, by means of an ejector, the full bobbin is transferred from its holder to a special bobbin skip. This known device for bobbin exchange entails a quite considerable expense in construction because of the multiplicity of movements that must be executed. In addition, this bobbin exchanger occupies considerable space because it has to carry along a large storage skip for empty tubes. Also, there is further expense in arranging the empty tubes at the place where they are to be dispensed.
It is also known (German Pat. No. 1,166,504) that a stationary bobbin exchanger can be disposed at each spinning assembly, each said spinning assembly being equipped with an empty-tube skip for storing its own empty tubes. The technical outlay is very high in this case also because an open-end spinning frame comprises about 200 spinning assemblies, so that there have to be 200 bobbin exchangers also.
The invention is addressed to the problem of building an open-end spinning frame and the travelling device of the mentioned type in such a way that manufacturing costs will be kept low without having to accept unfavorable operating conditions. The invention contemplates that each spinning assembly is provided with a storage place for an empty tube in the path of motion of an empty tube engaging device of the travelling device. The invention also contemplates that the empty tube engaging device effects an opening of the bobbin holder and lifting of the bobbin off of the friction roll.
In this way a semiautomatic device is developed, based on the premise that it does not require too much effort on the part of an operator to place the empty tubes manually at the individual spinning assemblies because this work is done at relatively long intervals. The necessary parts of the travelling device for execution of the work step can be limited to a minimum, particularly because the device that engages the empty tube also takes over the bobbin ejection function. In this arrangement it is preferably provided that the empty tubes already have a first winding which on the one hand serves as a yarn reserve for further processing and on the other hand is available for a starter winding, so that after bobbin exchange with a possible yarn break, yarn is present on the empty tube that allows automatic piecing. Here it is also preferably provided that there will be a planned interruption of the spinning process in the bobbin exchange, especially if it is provided that a cleaning of the spinning assembly will be done with an exchange of bobbins. In this case it can be provided that the travelling device will be a component of a cleaning device or will be combined with a travelling cleaning device in some other way.
In an advantageous embodiment of the invention, the depot devices with the empty tubes are provided with axially fixed stops that are oriented to the bobbin holder of the appurtenant spinning assembly in such a way that the empty tubes are held in a position that is parallel to their position of incorporation in the bobbin holder. We thus have the advantage that the work of setting up and positioning the empty tubes need not be done by the travelling device, so that the empty tube engaging device of the travelling device only has to execute a simple motion in one plane.
In one embodiment of the invention it is provided that the depot devices for empty tubes are disposed at each spinning assembly on a piece on the bobbin holder. Thus the path that the empty tube has to negotiate to its position of incorporation in the bobbin holder is very short. The empty tube engaging device can then be correspondingly simple.
In another embodiment of the invention it is provided that the depot devices for the empty tubes for the spinning assemblies are disposed on a carrier rod running in the long direction of the machine. This type of arrangement of the depot devices allows simple operation because the depot devices are readily accessible. It is also possible to orient the depot devices on the carrier rod in a simple way, exactly to the bobbin holder of the appurtenant spinning assembly and to the empty tube engaging device of the travelling device.
In an advantageous embodiment of the invention it is provided that the device that engages the empty tubes is equipped with spring tongs that grip an empty tube, in which tongs an empty tube can be clipped in at its periphery, and can be removed from the stationarily disposed depot device. With this embodiment the former customary relatively expensive gripping devices with their drives can be replaced without difficulties in function.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, several embodiments in accordance with the present invention.